We compare the accuracy of several emissive probe techniques
for
measurements of the plasma potential, including various
inflection point
methods, saturated floating potential, and separation point.
Uncertainties
due to voltage drop across the hot filament wire, space-charge
effects,
secondary electron emission (SEE) and orbital motion effects
are studied
both theoretically and experimentally. In particular, it is
shown that the
probe dc heating can cause a non-uniform electron emission and
collection
across the filament wire. This can reduce the accuracy of probe
measurements.

*Work supported by the US DOE.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.DPP.JP9.23